Our solution


The need

The European Council adopted in 2007 ambitious energy and climate change objectives for 2020 – to reduce greenhouse gas emissions by 20%, rising to 30% if the conditions are right efficiency. Despite of the existing strategy, it seems is currently unlikely to achieve all the 2020 targets, as reported by the European Commision. EU energy and climate goals have been incorporated into the Europe 2020 Strategy for smart, sustainable and inclusive growth. The urgent task for the EU is to agree the tools, which will make the necessary shift possible and thus ensure that Europe can emerge from recession on a more competitive, secure and sustainable path.

Increase of biogas production represents one of the possible solutions to approach 2020 targets. As a result, the utilization of biogas is a sharply expanding market in the EU. While in 2000 only a couple of hundred biogas plants were working in Europe, their number exceeded 8000 in 2011, and the expected growth will result in more than 40,000 plants in 2020. The major advantage of biogas to other renewable energy sources:

  • flexibility. It can be transformed to electricity or heat easily, or it can be injected into the existing natural gas grid. Further compressed biogas, is a CNG like fuel, that can be used in transportation
  • it reduces dependency on foreign energy sources (~40% of natural gas used in EU is imported from Russia)

Although agriculture and waste water are the main sources of biogas, landfills, collecting municipal waste, have huge potential, too. There are about 3000 landfills operating in the EU, accepting ~100 million tons of municipal waste per year. The potential (theoretic) calorific energy content of the gas produced from such amount is ca. 24 billion kWh, equal to the energy need of ca. 2 million European households.

Despite the huge potential laying in the bio-methane content of landfill gas, only few plants target their conversion to fuel quality. The main barrier of improved utilization lies in its specific mixture: landfill gas contains 1.5-5% oxygen as opposed to biogas produced by conventional technologies. Oxygen must be eliminated, because of strict regulations and associated technical problems.

• Corrosion: O2 reacts with other compounds of the gas such as H2S and results in highly corrosive sulphuric acid.

• Safety: O2 in compressed methane increases the risk of explosion, thus reducing the possibility of compressing.

Several upgrading technologies are available for the conventional biogas but these methods alone cannot eliminate oxygen. They are inefficient and poorly economical for oxygen removal.

 

The solution

All  previously  developed  “state  of  the  art” biogas  purification  technologies  show  a  “weak point”: the reduction of the oxygen content and hydrogen sulphides by membrane technology is a complex process, associated with environmental pollution and therefore costly in a long run.

The NOO2 project is developing a novel technology which is the combination of oxidative and anoxic desulfurization processes for the elimination of oxygen and sulfur in a two stage biological trickling reactor setup.

NOO2 project aims to develop an oxygen elimination technology according following to the scheme:

Flowchart

The integration of these microbiological processes into the existing “traditional” gas cleaning process, tailored  to  the  specific  biogas  gas  components will  allow  to  perform  biogas  upgrading  much more efficiently and environmentally friendly making it more cost-effective than ever before.

 

Innovation

The key innovation of the NOO2 proposal is the combination of oxidative and anoxic desulfurization process for elimination of oxygen in a two stage biological trickling reactor setup.
Some of the main advantages of using biotrickling system over the existing membrane technic are:

  • As opposed to the currently applicable system of  O2  removal  (membrane  separation),  the developed  NOO2  biotrickling  reactor  would  be compatible  with  all  kinds  of  biogas  upgrading processes
  • The operation of biotrickling is much cheaper than oxygen removal by membranes.  The planned biotrickling unit requires only the addition of  cheap  reagents  (such  as  NaNO3  or  NaHS) in  a  controlled  way  and  no  additional  supply of  nutrients  or  heating.  Even,  nitrate-enriched waste  water  can  be  used  as  nitrate  source, reducing also nitrate concentration of the waste water effluent
  • The  construction  and  maintenance  costs  of the designed system will be lower than that of a membrane  system,  no  need  for  high  pressure units,  no  need  for  expensive  membrane (changeable yearly)
  • The purified biogas of fuel quality can be transformed to electricity or heat  easily, can  be  injected  into  the existing  natural  gas  grid or can be handled as compressed natural gas (CNG) used in transportation